CN110831773A

CN110831773A - Method for printing 3D micro-optical image on packaging system

Info

Publication number: CN110831773A
Application number: CN201880044961.9A
Authority: CN
Inventors: G·R·梅多斯; H·德布
Original assignee: Procter and Gamble Co
Current assignee: Procter and Gamble Co
Priority date: 2017-07-05
Filing date: 2018-07-03
Publication date: 2020-02-21
Anticipated expiration: 2038-07-03
Also published as: WO2019010149A1; JP2022044672A; CN110831773B; JP2023160940A; US20190009483A1; EP3424740A1; JP2020524097A; MX2019015686A; EP3424740B1

Abstract

The present invention relates to a method for printing a 3D micro-optical image on a packaging system in an in-line method, the method comprising providing a substrate, printing a plurality of images on at least a portion of a first major surface of the substrate, applying a transparent varnish layer on the printed first major surface of the substrate, and forming a plurality of relief features on an outer surface of the varnish layer, wherein the relief features are microlenses.

Description

Method for printing 3D micro-optical image on packaging system

Technical Field

The invention relates to a method for printing a 3D micro-optical image on a packaging system and a 3D micro-optical image packaging system.

Background

Films for products and packages can benefit from micro-sized patterns. Such patterns may provide various effects, such as: optical effects (e.g., lens effects, holographic effects), haptic effects (e.g., perceived softness), and/or functional effects (e.g., surface properties). The 3D effect can be achieved by using the moir é magnifier principle, in which the substrate comprises an image and a micro-sized pattern with a specific relative arrangement. Especially in the field of packaging systems, 3D micro-optical decoration techniques are of great interest, since they have a high impact on the first impression of a product and are used to attract the view of a consumer to stay on a certain product, with a high degree of line-of-sight attraction.

3D micro-optical films are provided by, for example, Nanoventions, Inc., Visual Physics,/LLC, Rolling Optics, AB, and Grapac Japan Co., Inc. Commercially available films may have an image printed on one side and a microlens printed on the other side, or an image printed in a groove shape on the same side with a continuous relief feature.

However, these commercially available films have some major drawbacks: when the image and the lens are on different sides of the substrate, the substrate must be transparent so that the image is visible from the side on which the lens is arranged. In the case where the relief features are continuous, the desired moir é (moir é) magnifier effect cannot be achieved.

Lenticular designs having extended lenses and continuous relief feature designs of 1mm or greater on flexible films or labels often provide undesirable characteristics such as reduced flexibility thereof.

Furthermore, known lenticular designs having a stretched lens of 1mm or more are generally not attractive to consumers due to the rough surface which gives an uncomfortable feeling when handling a packaging system having such a lenticular design on the outer surface.

Disclosure of Invention

Based on the above disadvantages, there is still a need for new methods of forming 3D micro-optical effects on a variety of substrates in a fast and cost-effective manner.

According to the present invention, a method of making a 3D micro-optical packaging system is provided. The method includes providing a substrate, printing a plurality of images on at least a portion of a first major surface of the substrate, applying a transparent varnish layer on the printed first major surface of the substrate, and forming a plurality of relief features on an outer surface of the varnish layer, wherein the relief features are microlenses.

The method allows the preparation of a variety of packaging systems printed with 3D micro-optical images providing moire magnifier effect on a variety of different substrates, which may be transparent as well as opaque. Microlens designs can be easily incorporated into flexible films and labels for packaging systems because they are typically thin and small. Microlens designs can be incorporated into packaging systems without significantly altering their characteristics in terms of suitability as packaging systems, such as their flexibility, thickness, weight, feel. Thus, the microlens design is suitable for use in a variety of packaging systems. They can provide a smooth surface, thereby attracting consumers. They may be thin and light, thereby maintaining the flexibility of the flexible film and label.

Brief description of the invention

The invention relates to a method for printing 3D micro-optical images on a packaging system. The method includes providing a substrate having a first major surface and a second major surface; printing a plurality of images on at least a portion of the first major surface of the substrate to provide a substrate having a printed first major surface; applying a transparent varnish layer on the printed first major surface of the substrate, wherein the varnish layer has an inner surface in contact with the printed first major surface of the substrate and an outer surface facing away from the substrate; and forming a plurality of relief features on an outer surface of the varnish layer, wherein the relief features are microlenses.

The invention also relates to a 3D micro-optical image packaging system comprising a substrate having a first major surface and a second major surface, a plurality of images on at least a portion of the first major surface, a transparent varnish layer on the first major surface of the substrate overlying the printed images, wherein the varnish layer has an inner surface in contact with the printed first major surface of the substrate and an outer surface facing away from the substrate, wherein the varnish layer has a plurality of relief features on the outer surface of the varnish layer, and wherein the relief features are microlenses.

Drawings

While the specification concludes with claims particularly pointing out and distinctly claiming the present invention, it is believed that the present invention will be better understood from the following description when taken in conjunction with the accompanying drawings, wherein:

FIG. 1 schematic representation of an ink jet printing process

FIGS. 2 a-2 d schematic diagrams of the in-mold labeling process

FIGS. 3 a-3 c schematic diagrams of a transfer process

FIG. 4 schematic representation of a rotogravure printing process

FIG. 5 schematic diagram of a screen printing method

FIG. 6 schematic illustration of a letterpress printing process

FIG. 7 schematic diagram of an offset printing process

FIG. 8 schematic of a flexographic printing process

FIGS. 9 a-9 c schematic diagrams of printed substrates bearing images

FIGS. 10 a-10 f top views of a varnish layer with microlenses

FIGS. 11 a-11 g side views of a clearcoat layer with embossed features

FIG. 12 schematic representation of a 3D micro-optic image from the perspective of an observer

FIG. 13 schematic diagram of a method of making a 3D micro-optic image packaging system

FIG. 14 is a flow chart for preparing a 3D micro-optic image packaging system

FIG. 15 schematic diagram of a flexographic printing press for making a 3D micro-optic image packaging system

FIG. 16 flow chart for preparing a patterned flexographic printing plate or casting plate

FIGS. 17 a-17 j end views of steps of preparing a patterned flexographic printing plate or casting plate

FIG. 18 flow chart for preparing a patterned flexographic printing plate or casting plate

FIGS. 19 a-19 b end views of steps of preparing a patterned flexographic printing plate or casting plate

FIG. 203D side view of a micro-optic image packaging system

Detailed Description

A "3D micro-optical image packaging system" according to the present invention is a packaging system having an image printed on a surface thereof, which image exhibits a 3D optical effect to a viewer.

A "substrate" according to the present invention is all materials suitable for printing and having a first main surface and a second main surface. Preferably, the substrate has a sheet-like shape.

A "rigid substrate" according to the present invention is a substrate that resists deformation in response to an applied force and is therefore not suitable for an in-line printing process.

A "relief feature" according to the present invention is a feature that protrudes from the minimum extent of the varnish in a direction perpendicular to the substrate surface.

The "image size" defines the maximum extension of the image.

The term "micro" according to the present invention means a stretch of less than 1mm, preferably 1 μm to less than 1 mm.

A "microimage" according to the present invention is an image having an image size of less than 1 mm.

A "microlens" according to the present invention is a lens having a maximum height and a maximum width of less than 1 mm.

According to the invention, the "inter-image distance" characterizes the minimum distance between the images. Thus, the "distance between relief features" characterizes the minimum distance between relief features.

"height" according to the present invention is defined as the extension in a direction perpendicular to a surface. For example, the height of the varnish layer is a stretch in a direction perpendicular to the substrate surface. For example, the height of the relief features is the difference between the maximum stretching of the varnish in a direction perpendicular to the substrate surface and the minimum stretching of the varnish in a direction perpendicular to the substrate surface.

The height, when used in conjunction with a layer, may also be referred to as "thickness", wherein the thickness of the structured layer is described as the minimum extension of the layer in a direction perpendicular to one surface.

According to the invention "a plurality" is more than one.

According to the invention, "transparent" means that the material has a transparency (I/I) of at least 0.5 in the wavelength range from 400nm to 780nm and a material layer thickness of 10mm₀)。

According to the invention, "porous" is defined as a material having a pore size of at least 1 nm. Materials with lower pore sizes (i.e., in the sub-nanometer range) or that are non-porous are "non-porous" materials. Pore size can be determined by ASTM D4404.

A "photopolymer" according to the pending application is a polymeric material that can be cured by electromagnetic radiation (e.g., light).

The invention relates to a method for printing 3D micro-optical images on a packaging system, comprising

a. Providing a substrate having a first major surface and a second major surface;

b. printing a plurality of images on at least a portion of the first major surface of the substrate to provide a substrate having a printed first major surface;

c. applying a transparent varnish layer on the printed first major surface of the substrate, wherein the varnish layer has an inner surface in contact with the printed first major surface of the substrate and an outer surface facing away from the substrate; and

d. a plurality of relief features are formed on an outer surface of the varnish layer, wherein the relief features are microlenses.

And a step a.

The method includes providing a substrate having a first major surface and a second major surface. The substrate may be flexible or rigid. Preferably, the substrate is rigid.

The substrate may be of any shape. For example, the substrate may be sheet-like, e.g. a sheet or a film, having the shape of the packaging system, or having the shape of a part of the packaging system. The substrate may have any thickness. For example, the substrate has a thickness of 1 μm to 10cm, or 2 μm to 5cm, or 5 μm to 1cm, or 10 μm to 5mm, or 20 μm to 1 mm.

The substrate may comprise a polymeric material, glass, wood, stone, ceramic, metal, woven or non-woven fabric, paper, or combinations thereof. Preferably, the substrate comprises a polymeric material. More preferably, the polymeric material is selected from the group consisting of high density polyethylene, low density polyethylene, linear low density polyethylene, polypropylene, polyethylene terephthalate, and combinations of two or more thereof.

The rigid substrate may comprise a polymeric material, glass, wood, stone, ceramic, enameled metal, or combinations thereof. Preferably, the substrate comprises a polymeric material. More preferably, the polymeric material is selected from the group consisting of high density polyethylene, low density polyethylene, linear low density polyethylene, polypropylene, polyethylene terephthalate, and combinations of two or more thereof.

The substrate may also be flexible. The flexible substrate may comprise a polymeric material, a metallic material, a woven or non-woven fabric, paper, or a combination thereof, preferably a polymeric material. The flexible substrate is preferably a plastic foil or a plastic film. The polymeric material is preferably selected from the group consisting of high density polyethylene, low density polyethylene, linear low density polyethylene, polypropylene, polyethylene terephthalate, and combinations of two or more thereof.

The substrate may be porous or non-porous. The porous substrate may for example be a microporous substrate having pore sizes of less than 1 μm, for example less than 500nm or in the range of 1nm to 500nm or 2nm to 200 nm. Preferred substrates according to the present invention are non-porous.

And b, step b.

The method includes printing a plurality of images on at least a portion of the first major surface of the substrate to provide a substrate having a printed first major surface.

The image may be printed by any method known in the art suitable for printing an image on a major surface of a substrate. Preferably, the image is printable by a method selected from the group consisting of ink jet printing, in-mold labeling, transfer printing, rotogravure printing, screen printing, letterpress printing, offset printing and flexographic printing. Such printing methods are well known in the art.

Ink jet printing generally includes a high pressure pump that directs liquid ink from a reservoir through a gun body and micro-nozzles that form ink droplets. The droplets are subjected to an electrostatic field as they are formed so that each droplet can be individually charged. They are then directed by an electrostatic deflection plate to print on the substrate. This method is described in more detail below with reference to FIG. 1

In-mold labeling is a plastic molding process that is used to shape a plastic material while decorating its surface. The carrier foil carrying the decoration to be transferred onto the plastic part is placed in the mold of the open molding device. The foil is fixed in the mould by vacuum or static electricity. A plastic material such as polypropylene is introduced into the mold in a molten or softened state. The molding device is closed. The plastic material is formed into the desired shape by heat and/or pressure. In this step, the carrier foil and the plastic material are fused to form a printed substrate, wherein the printing is an integral part of the substrate. This method is described in more detail below with reference to fig. 2 a-2 d.

Transfer typically involves transferring liquid-based ink from a pad to a substrate using a transfer device. Suitable transfer means are, for example, engraved metal plates, such as copper or steel plates, or structured polymer stamps, such as rubber stamps. This method is described in more detail below with reference to fig. 3 a-3 c.

Rotogravure printing is a printing method using a rotary printing press, which involves engraving an image on an image carrier, i.e. a cylinder that is part of the rotary printing press. The ink is applied directly to the cylinder and transferred from the cylinder to the substrate. This method is described in more detail below with reference to fig. 4.

Screen printing is a printing technique in which a design is applied to a screen used to transfer ink to a substrate. The mesh screen may be made of any mesh material, preferably polyethylene terephthalate. The open mesh is filled with ink. The ink-filled mesh is brought into contact with the substrate, which causes the ink to wet the substrate and be pulled out of the mesh. This method is described in more detail below with reference to fig. 5.

Letterpress printing is a technique of relief printing using a printing press. Thus, many replicas can be made by repeated direct embossing of the inked raised surface with a sheet or roll of the substrate. The method comprises the following steps: assembling, i.e., assembling the movable pieces to form a desired image; application, i.e. arranging the various components of the combining step to form a form that can be used on a printing press; locking, i.e. fixing the assembly to avoid printing errors; and embossing of the inked member and pressing them onto the substrate surface. This method is described in more detail below with reference to fig. 6.

Offset printing is a printing process in which an inked image is indirectly transferred from an image carrier plate to a substrate surface. The offset printing process is based on oil and water repellency. It uses a flat image carrier plate, i.e. a plate with a flat non-engraved surface on which the image to be printed gets ink from an ink roller. The non-printing areas of the image carrier sheet attract the water-based film so that these areas remain free of ink. The image carrier sheet transfers the image to a transfer blanket, which is then printed on the substrate surface. Generally, the process is carried out continuously using a rotary printing press in which the image carrier sheet and the transfer blanket are rotary cylinders, i.e., a plate cylinder and an impression cylinder, and the substrate passes between the impression cylinder and the blanket cylinder. This method is described in more detail below with reference to fig. 7.

An exemplary flexographic printing method is described below: a positive mirror master for forming an image in a flexographic printing plate. Such plates may be prepared by analog or digital platemaking processes, which are described in more detail below. Herein, the image area is raised above the non-image area on the board. The ink was transferred to the plate at a uniform thickness. The substrate is then pressed onto the inked flexographic printing plate, for example, by sandwiching the substrate between a plate and an impression cylinder, thereby transferring the image. To dry the ink, the ink may be cured using different methods, such as passing the substrate through a dryer or irradiating the substrate with ultraviolet light. In the case of images having multiple colors, it is preferable to use a different flexographic printing plate for each color. In this case, a plate is prepared and placed on a cylinder placed in the printing press. To complete the image, the image from each flexographic printing plate is transferred to a substrate. Flexographic printing is preferred for printing flexible substrates. This method is described in more detail below with reference to fig. 8.

The size, shape and color of the image printed on the substrate are not limited. The images may be the same or different. Preferably, at least some of the images are identical. For example, all images are the same. The printing surface may comprise two or more, for example two or three or four or five or more, arrays of images, wherein the images within the arrays are the same.

The images may be arranged in a regular pattern. Where the substrate comprises an array of images, the images within the array are preferably arranged in a regular pattern. The patterns in the different arrays may be the same or different.

Preferably, the image is a microimage. The image size may be at least 20 μm, preferably in the range of 20 μm to 300 μm, for example in the range of 50 μm to 100 μm. The images may have the same or different image sizes. Where the substrate comprises an array of images, the images within the array preferably have the same image size. The image sizes in different arrays may be different.

The distance between the images may be in the range of 1 μm to 1mm, preferably in the range of 5 μm to 100 μm, more preferably in the range of 10 μm to 50 μm. It may be preferred that the distance between the images is in the order of the image sizes, e.g. not more than 50% or not more than 30% or not more than 10% difference. The ratio of image size to image distance may be in the range 10:1 to 1:100, preferably in the range 5:1 to 1:50 or 2:1 to 1: 10. Where the substrate comprises an array of images, the images within the array preferably have the same image distance. The image distances may be different in different arrays.

Examples of suitable arrangements of images are shown in fig. 9 a-9 c.

And c, step (c).

The method comprises applying a layer of transparent varnish on the printed first major surface of the substrate. The varnish layer has an inner surface in contact with the printed first major surface of the substrate and an outer surface facing away from the substrate.

According to the invention, the varnish layer may be formed by applying the varnish composition onto the printed first main surface of the printed substrate and subsequently hardening to form the varnish layer. For example, the varnish composition may be applied by a spray coating, drop coating, roll coating, dip coating, spin coating, or dip coating process.

The varnish composition may be any varnish known in the art that is compatible with the corresponding substrate material, which is suitable for coating flexible substrates and for in-line processes. Preferably, the varnish is thermally curable, photocurable or both, preferably UV curable.

The varnish may, for example, comprise a polyolefin such as polyethylene (preferably LLDPE, LDPE, MDPE, HDPE) or polypropylene, a polyester such as polyethylene terephthalate, a polyamide such as nylon, a halogenated vinyl resin such as polyvinyl chloride, poly (meth) acrylates, biodegradable plastics, polyurethanes, alkyds, epoxies, or a combination of two or more thereof.

Biodegradable plastics are plastics, in particular bioplastics, which are decomposed by living organisms, such as bacteria. They may be selected, for example, from aliphatic polyesters, polyanhydrides, polyvinyl alcohols, starch derivatives, cellulose esters, such as cellulose acetate and nitrocellulose, and polyethylene terephthalate. Bioplastics are plastics derived from renewable biomass sources such as vegetable fats and oils, corn starch or microorganisms, preferably consisting of starch, cellulose or biopolymers. They may for example be selected from starch-based plastics, cellulose-based plastics, protein-based plastics, polyhydroxyalkanoates such as poly-3-hydroxybutyrate, polyhydroxyvalerate, polyhydroxyhexanoate, polylactic acid and polyhydroxyurethanes.

Preferably, the varnish is an acrylic varnish. The acrylic varnish according to the invention may be a varnish comprising: poly (meth) acrylates, i.e., polyacrylic acid, polymethacrylic acid, polyacrylic acid derivatives such as carboxylates, esters, amides, or salts thereof, polymethacrylic acid derivatives such as carboxylates, esters, amines, or salts thereof, copolymers thereof, or combinations of two or more thereof. Preferably, the salt is an alkali metal salt, preferably a sodium salt, in particular sodium polyacrylate.

The acrylic varnish preferably comprises structural units of the formula (I) or (II)

Wherein X and Y may be selected from N and O, preferably O; and

R¹and R²Can be selected from H, C₁-C₁₈Alkyl radical, C₁-C₁₈Alkenyl radical, C₆-C₁₄Aryl, preferably selected from H, methyl and ethyl.

And d, step d.

The method includes forming a plurality of relief features on an outer surface of the varnish layer. The relief features may be formed on the clearcoat layer by any method known in the art suitable for structuring a coating in an in-line process.

The relief features on the varnish layer may be formed by a method similar to the printing method described above, in which the relief features are printed instead of the image. Preferably, the relief features may be formed by a method selected from transfer printing, rotogravure printing, and flexographic casting.

The relief features may be formed by transfer printing. The general process of forming the relief features by transfer is based on the transfer method of the printed image as described above. The transfer device includes posts whose lower surfaces are in contact with the substrate, which have the inverse shape of the relief features to be printed on the substrate, e.g., in reverse image of part of a sphere.

The embossed features may be formed by rotogravure printing. A general procedure for forming embossed features by rotogravure printing is in accordance with the rotogravure printing method of printing an image as described above. The surface of the image carrier cylinder of the rotary printer has a concave shape that is the inverse of the shape of the relief features to be printed on the substrate, e.g., a partial sphere that is the inverse.

Preferably, the relief features are formed by a film-free casting process using a flexographic casting plate. In the film-less casting method, a mirror image master of the relief features is formed in the flexographic casting plate. Methods of making such panels are described in more detail below. The embossed feature region protrudes above the non-embossed feature region on the sheet. The varnish was transferred to the plate. The printed substrate is then pressed onto a flexographic casting plate, for example by sandwiching the printed substrate between the plate and an impression cylinder, thereby transferring the varnish and thereby forming the relief features.

For curing the varnish, different methods such as thermal curing or UV curing can be used. Preferably, the varnish is cured by UV curing.

The relief features formed on the outer surface of the varnish layer are microlenses. According to the invention, the microlenses are discontinuous relief features, i.e. discontinuous in one direction of the substrate, wherein the ratio of the minimum extension to the maximum extension of one relief feature is in the range of 1:1000 to 1:1, preferably 1:100 to 1:1, more preferably 1:10 to 1:1. From a top view, the microlenses may be circular or polygonal, such as circular, elliptical, polygonal with 3 or 4 or 5 or 6 or 8 or more than 8 angles. Preferably, the polygonal microlenses are selected from triangular, square, rectangular, diamond-shaped, and regular polygonal shapes such as pentagonal, hexagonal, or octagonal. Examples of the shapes of the discontinuous relief features are shown in fig. 10 a-10 f.

The relief features may, for example, have a triangular, trapezoidal, square, rectangular, or partially circular shape when viewed from a side view. The preferred side view shape of the relief features is shown in fig. 11 a-11 g.

Preferably, the relief features are in the shape of partial spheres, partial ellipsoids, cylinders, cones, tetrahedrons, pyramids, hexagonal pyramids, octagonal pyramids, cubes, cuboids, pentagonal prisms, hexagonal prisms. The relief features are preferably in the shape of part spheres.

The relief features may be arranged in a regular pattern. Where the substrate comprises an array of relief features, the relief features within the array are preferably arranged in a regular pattern. The patterns in the different arrays may be the same or different.

Preferably, the relief features have a height in the range of 50nm to 150 μm, preferably in the range of 10 μm to 30 μm.

Preferably, the size of the relief features is at least 20 μm, preferably in the range 20 μm to 300 μm, for example in the range 50 μm to 100 μm. The relief features may have the same or different dimensions. Where the substrate comprises an array of relief features, the relief features within the array are preferably of the same size. The dimensions of the relief features in different arrays may be different.

Any repeating pattern of relief features and images, and their arrangement relative to each other, may be used as long as an interference pattern (moire) magnification effect is formed. This principle is illustrated in fig. 12.

The pattern of the relief features and the image may be the same or different. Preferably, the relief features and the image have the same pattern. It may also be preferred that each image is superimposed with a relief feature.

The ratio of the maximum diameter of the relief feature to the maximum diameter of the image may be at least 1, for example a ratio in the range 50:1 to 1:10, or 10:1 to 1:2, or 5:1 to 1:1.2, or 2:1 to 1:1, more preferably in the range 1.3:1 to 1:1. Where different arrays of image and/or relief features are arranged on the substrate, the above-mentioned diameter ratios preferably relate to at least one array, more preferably to all arrays.

It is most preferred in the present invention that the relief features and the images have the same pattern, with each image superimposed with a relief feature having at least the same maximum diameter as the image and centrally disposed over the top of the image.

A preferred example of this method is described in more detail in connection with fig. 13-15.

FlexibilityLithographic printing plate/flexographic plate casting plate

In the case of printing an image by flexographic printing, a flexographic printing plate is preferably used. Where the relief features are formed by a film-less casting process, a flexographic casting plate is preferably used.

The flexographic printing plate, the flexographic casting plate, or both may be made of a plastic material, such as polypropylene, high density polyethylene, low density polyethylene, linear low density polyethylene, polyethylene terephthalate, and combinations of two or more thereof, preferably polypropylene.

The flexographic printing plate, the flexographic casting plate, or both may be flexible or rigid, preferably flexible.

The flexographic printing plate, the flexographic casting plate, or both may be prepared by a process comprising injection molding, blow molding, embossing, printing, engraving, or a combination thereof.

According to the present invention, it may be preferred that the flexographic printing plate, the flexographic casting plate or both are prepared by a process comprising the steps of:

i. providing a flexible patterned substrate;

pressing the patterned surface of the patterned substrate onto the uncured soft photopolymer plate to provide a patterned uncured photopolymer plate; and

curing the patterned uncured photopolymer plate to provide the patterned flexographic plate.

For example, a patterned substrate can be pressed into an uncured soft photopolymer plate to form a patterned flexographic printing plate or casting plate that can be used to impart a micro-scale pattern into a curable coating on a film. Such a simulated imprinting process does not require the use of precise equipment controls or washing steps, as is the case with known applications today. The resulting flexographic or cast plate can be used with commercially available coatings on conventional flexographic printing equipment and can last thousands of cycles, so the plate is also simple to use and inexpensive. This method is described in more detail in connection with fig. 16 and fig. 17 a-17 j.

The patterned substrate may be flexible or rigid. Flexible patterned substrates of the present invention are commercially available in the form of flexible patterned films, such as CAST AND CURE holographic films (CAST AND CURE holographic films) available from Breit Technologies (Overland Park, Kansas, United States). The flexible patterned substrate can be any suitable flexible material (e.g., a thin, flexible sheet-like material), with a suitable pattern of embossed features, and can be processed as described in fig. 16. Examples of flexible patterned substrates include: textured paper, fabric, micro-embossed film, optical lens film. Rigid patterned substrates, such as metal sheets, molded plastic sheets, or silicon wafers, are also suitable for use in the present invention. Preferably, the patterned substrate is flexible.

The uncured soft photopolymer plate can have a different total thickness, for example, from 0.1mm to 10.0mm, or from 0.5mm to 5mm, or from 0.8mm to 3mm, preferably from 1.0mm to 2 mm. The uncured soft photopolymer plate may for example have a thickness of 1.14mm or 1.70 mm. However, it is also possible to provide uncured soft photopolymer plates without a protective mask. Uncured soft photopolymer is commercially available in the form of flexographic plates (with and without a mask layer) such as: CYREL FAST (e.g., types DFUV, DFR, DFM, and DFP) flexographic plates available from DuPont (Wilmington, Delaware, United States), or flexographic plates available from MacDermid, Inc. (Morristown, Tennessee, United States), such as types UVR, MAX, and MVP. The uncured soft photopolymer plate can be made of one or more suitable materials (such as a mixture of monomers, oligomers, and/or photoinitiators; common forms include acrylates and silicones) that are cured to a hardened state by exposure to visible and/or ultraviolet light, as is known in the art.

(i) providing a rigid patterned substrate; and

(ii) a polymeric material, preferably polypropylene, is applied in an injection molding process on a rigid patterned substrate to provide a patterned flexographic plate.

The rigid patterned substrate may be made of a material selected from the group consisting of: polymeric materials, metallic materials, glass, ceramics, minerals, combinations of two or more thereof, and composites of one or more of the foregoing materials. Preferably, the rigid patterned substrate is a patterned steel plate.

The pattern in the rigid substrate may be formed by any suitable method for patterning the rigid substrate, such as injection molding, blow molding, embossing, printing, engraving, or combinations thereof. Preferably, the pattern of the rigid patterned substrate is prepared by laser pulse engraving.

The polymeric material may be a thermoplastic resin, for example selected from the group consisting of polypropylene, high density polyethylene, low density polyethylene, linear low density polyethylene, polyethylene terephthalate, and combinations of two or more thereof. Preferably, the polymeric material is polypropylene.

The polymeric material may be applied to the rigid patterned substrate during an injection molding process. The general operation of injection molding is well known in the art. For example, the following procedure may be followed:

the polymeric material is heated to a molten or malleable state. The material is then driven through a nozzle onto a rigid patterned substrate that serves as a mold cavity. The plastic material is then cooled on the mold, for example by the mold being kept cool, by external cooling, or both. This method is described in more detail in connection with fig. 18 and fig. 19 a-19 b.

The invention also relates to a 3D micro-optical image packaging system comprising:

A. providing a flexible substrate having a first major surface and a second major surface;

B. a plurality of images on at least a portion of the first major surface;

C. a layer of transparent varnish on the first major surface of the substrate on which the printed image is superimposed.

Wherein the varnish layer has an inner surface in contact with the printed first main surface of the substrate and an outer surface facing away from the substrate. In addition, the clearcoat layer has a plurality of relief features on an outer surface of the clearcoat layer.

The preferred embodiments of the flexible substrate, image, varnish layer and relief features described above in relation to the method according to the invention are also applicable to the flexible substrate, image, varnish layer and relief features of the 3D micro-optical image packaging system. An exemplary 3D micro-optic image packaging system is shown in fig. 20.

The 3D micro-optical image packaging system is suitable for use in food and non-food packaging systems, such as for packaging personal care and medical products, household and horticultural products, entertainment and media products, electronic devices, toys, sporting products.

Detailed description of the embodiments

1) Method for printing 3D micro-optical images on a packaging system, the method comprising

c. applying a layer of transparent varnish on the printed first major surface of the substrate, wherein the layer of varnish has an inner surface in contact with the printed first major surface of the substrate and an outer surface facing away from the substrate; and

d. forming a plurality of relief features on an outer surface of the varnish layer, wherein the relief features are microlenses.

2) The method of embodiment 1), wherein the substrate is a rigid substrate.

3) The method according to any one of the preceding embodiments, wherein the substrate is a polymeric material selected from the group consisting of high density polyethylene, low density polyethylene, linear low density polyethylene, polypropylene, and polyethylene terephthalate.

4) The method of any one of the preceding embodiments, wherein the substrate is non-porous.

5) The method according to any one of the preceding embodiments, wherein the substrate is a rigid non-porous polymeric material selected from the group consisting of high density polyethylene, low density polyethylene, linear low density polyethylene, polypropylene, and polyethylene terephthalate.

6) The method according to any of the preceding embodiments, wherein the image is printed by a method selected from the group consisting of inkjet printing, in-mold labeling, transfer printing, rotogravure printing, screen printing, letterpress printing, offset printing, and flexographic printing.

7) The method of any one of the preceding embodiments, wherein the image is a microimage.

8) The method according to any one of the preceding embodiments, wherein the images are arranged in a regular pattern.

9) The method according to any one of the preceding embodiments, wherein the image size is at least 20 μm, preferably in the range of 20 to 300 μm.

10) The method according to any one of the preceding embodiments, wherein the distance between the images is in the range of 1 μm to 1mm, preferably 5 μm to 100 μm, more preferably 10 μm to 50 μm.

11) The method according to any one of the preceding embodiments, wherein the image size is at least 20 μm, preferably in the range of 20 to 300 μm, and wherein the distance between the images is in the range of 1 to 1mm, preferably 5 to 100 μm, more preferably 10 to 50 μm.

12) The method of any of the preceding embodiments, wherein the varnish is thermally curable, photo-curable, or both, preferably UV curable.

13) The method according to any one of the preceding embodiments, wherein the varnish is an acrylic varnish.

14) The method of any one of the preceding embodiments, wherein the relief features on the varnish layer are formed by a film-free casting process using a flexographic casting plate.

15) The method according to any one of the preceding embodiments, wherein the relief features have a height in the range of 50nm to 150 μ ι η, preferably in the range of 10 μ ι η to 30 μ ι η.

16) The method according to any one of the preceding embodiments, wherein the size of the lens is at least 20 μm, preferably in the range of 20 to 300 μm.

17) The method of any one of the preceding embodiments, wherein the relief features have the shape of the partial spheres.

18) The method according to any one of the preceding claims, wherein the relief features have a height in the range of 50nm to 150 μ ι η, preferably 10 μ ι η to 30 μ ι η, a diameter of at least 20 μ ι η, preferably in the range of 20 μ ι η to 300 μ ι η, and the shape is a partial spherical shape.

19) The method according to any one of the preceding embodiments, wherein the relief features and the images have the same pattern, preferably wherein each image is superimposed with a relief feature having at least the same maximum diameter as the image and centrally disposed over the top of the image.

20) The method of any of the preceding embodiments, wherein the image is printed by flexographic printing using a flexographic printing plate, or wherein the relief features are formed by a film-free casting process using a flexographic casting plate, or both, and wherein the flexographic printing plate, the flexographic casting plate, or both are prepared by a process comprising injection molding, blow molding, embossing, printing, engraving, or a combination thereof.

21) The method of embodiment 20, wherein the flexographic printing plate, the flexographic casting plate, or both are made of a plastic material (preferably polypropylene).

22) The method of embodiment 20 or embodiment 21, wherein the flexographic printing plate, the flexographic casting plate, or both are flexible.

23) The method of any one of embodiments 20-22, wherein the flexographic printing plate, the flexographic casting plate, or both are prepared by a method comprising:

i. providing a flexible patterned substrate;

pressing the patterned surface of the patterned substrate onto an uncured soft photopolymer plate to provide a patterned uncured photopolymer plate; and

24) The method of any one of embodiments 20-22, wherein the flexographic casting plate is prepared by a method comprising:

(i) providing a rigid patterned substrate; and

(ii) applying a polymeric material, preferably polypropylene, in an injection molding process on the rigid patterned substrate to provide the flexographic casting plate.

25) The method of embodiment 24, wherein the rigid patterned substrate is a patterned steel plate.

26) The method of any of embodiments 24 or 25, wherein the pattern of the rigid patterned substrate is prepared by laser pulse engraving.

27)3D micro-optical image packaging system, the packaging system comprising

A. A substrate having a first major surface and a second major surface;

B. a plurality of images on at least a portion of the first major surface;

C. applying a layer of transparent varnish on the first major surface of the substrate overlying the printed image, wherein the layer of varnish has an inner surface in contact with the printed first major surface of the substrate and an outer surface facing away from the substrate; and wherein the varnish layer has a plurality of relief features on an outer surface of the varnish layer, wherein the relief features are microlenses.

Detailed description of the drawings

Fig. 1 illustrates an inkjet printing method. A high pressure pump 103 directs liquid ink 102 through a gun body and nozzle 105. The piezoelectric crystals 104 generate acoustic waves that break up the stream of ink 102 into droplets 106. The ink droplets are subjected to an electrostatic field by a charging electrode 107. In another electrostatic field 109, the droplets are directed by an electrostatic deflection plate 108 to print on the substrate 101, or allowed to continue undeflected into a collection tank 110 for reuse. The result is a substrate 101 with ink droplets 111 thereon to form an image.

Fig. 2 a-2 d show an in-mold labeling method. The molding device for mold labeling comprises two parts: comprising a lower part 201 of the mould 205 and an upper part 202 for closing the mould and filling the mould 205 with plastic material. In a first step, the printed label 203 is introduced into the mould 205 using the handling device 204. The handling device 204 is removed. The printed label 203 is secured in the mold 205 so that there are no air pockets or creases that adversely affect the product. The molding device is closed. A plastic material 206 is introduced into the mould 205 through an opening 207. After the heat and pressure treatment and subsequent cooling, the moulding device is opened and a moulded plastic material with a printed surface 208 is obtained.

Fig. 3 a-3 c illustrate a transfer method. The transfer device 302 includes a plurality of posts 303. The post 302 may dip the liquid-based ink 304 from the pad 301. The dipped ink 304 may then be transferred from the posts 303 of the transfer device 302 to the surface of the substrate 305. After the transfer device 302 is removed, a printed image 306 is disposed on the surface of the substrate 305.

Figure 4 shows a rotogravure printing process. Here, the substrate 401 is printed continuously by passing through the rotary printer in direction 406. The rotary press includes an intaglio cylinder 403 and an impression cylinder 402. The image is engraved on the intaglio cylinder 403. The gravure cylinder 403 is in contact with an ink reservoir 404. Excess ink is removed from the gravure cylinder 403 with a doctor blade 405 before contacting the major surface of the substrate 401 to be printed. The impression cylinder 402 applies pressure from the other side, i.e. on the second main surface of the substrate 401. Thereby obtaining a substrate having a printed surface.

Fig. 5 illustrates a screen printing method. Mesh 1901 with mesh 1902, preferably made of polyethylene terephthalate, is provided herein. Mesh 1901 is contacted with ink 1903, which causes the ink to fill mesh 1902. The ink-filled mesh is then brought into contact with a substrate 1904. Ink is squeezed from the mesh 1902 and onto a substrate 1904 using a squeezer 1906. The mesh 1901 is removed 1905 to provide a printed substrate 1907.

Fig. 6 illustrates a letterpress printing method. Bed 2001 is provided herein. In the bed 2001, the moving member 2002 is assembled to form an image. Moving part 2002 is inked such that the top surface of moving part 2002 is coated with ink 2003. Substrate 2004 is then pressed onto active 2002 such that inked surface 2003 contacts substrate 2004, thereby transferring ink onto substrate 2004 to provide printed substrate 2005.

Fig. 7 illustrates an offset printing method. Here, a substrate 501 is printed continuously by passing through a rotary printer in direction 502. The rotary printing press includes an impression cylinder 503, an offset cylinder 504, and a plate cylinder 505. The plate cylinder 505 is also in contact with a dampening unit comprising a fountain and dampening cylinder 507 and an inking unit comprising an ink fountain and inking cylinder 506. The inking and wetting units deliver ink and water to the plate cartridge 505. The plate cylinder 505 transfers the ink to the blanket covering the blanket cylinder 504. The substrate 501 is pressed against the blanket cylinder 504 by the impression cylinder 503, transferring the ink to the substrate to form a printed image.

FIG. 8 is a schematic of a flexographic printing process. The flexible substrate 601 passes through the flexographic printing press in the indicated direction 602. During passage through the flexographic printing press, an ink layer 603 comprising a plurality of images 605 is printed on the substrate 601 via ink stations 604, wherein each ink station 604 provides a portion of an image 605.

Fig. 9 a-9 c show schematic views of a printed substrate with different regular patterns of different images.

In fig. 10 a-10 f top views of a varnish layer with different top view shapes of the micro lenses are shown. Fig. 10a and 10b illustrate the circular shape of the relief features. Fig. 10 d-10 e illustrate the square shape of the relief features. Fig. 10f shows the diamond shape of the relief feature.

A side view of a varnish layer having a preferred side view shape of a relief feature is shown in fig. 11 a-11 g. Fig. 11a shows the triangular shape of the relief feature. Fig. 11b shows the trapezoidal shape of the relief feature. Fig. 11c shows a square shape of the relief feature. Fig. 11d and 11e show the rectangular shape of the relief features. Fig. 11f shows a relief feature in the shape of a partial sphere. Fig. 11g shows a relief feature in the shape of a partial ellipsoid.

Fig. 12 shows a schematic diagram of the principle of moire magnifier providing a 3D micro-optical image from the perspective of the viewer: a printed substrate with a regular pattern of micro-images 1001 is superimposed with a layer of varnish with circular micro-lenses 1002. The resulting 3D micro-optical image 1003 is caused by a moir é (moir é) magnification effect.

Fig. 13 is a flow chart showing the steps of printing a 3D micro-optical image on a packaging system. Step 1101 includes providing a substrate. Step 1102 includes printing a plurality of images on a first major surface of a substrate. Step 1103 comprises applying a varnish layer on the printed first major surface of the substrate. Step 1104 includes forming a plurality of relief features on an outer surface of the varnish layer. The result 1105 is the 3D micro-optical image packing system resulting from steps 1101-1104. The 3D micro-optical effect is caused by the overlap of the image and the relief features, resulting in a moir é (moir é) magnification effect.

Fig. 14 shows a method according to the invention. A substrate 1201 is provided. In a flexographic printing process, an image is printed on a substrate 1201 by an ink station 1202 to provide a printed substrate with an ink layer 1203 having a microimage 1204 on one surface of the substrate 1201. A flexographic casting plate 1205 is then used to apply the varnish layer 1206 and cast the micro-image superimposed varnish microlenses 1207.

Fig. 15 is a schematic diagram of a flexographic printing press adapted to print 3D micro-optical images on a packaging system. The substrate 1301 passes through the flexographic printing machine in the indicated direction 1305. During passage through the flexographic printing press, an ink layer 1302 including a plurality of images 1303 is printed on a substrate 1301 via ink stations 1306, wherein each ink station 1306 provides a portion of an image 1303. A varnish layer including a plurality of relief features 1034 is cast via a varnish station 1307.

FIG. 16 is a flow chart showing the steps of preparing a patterned flexographic printing plate or casting plate according to the present invention. Step 1401 comprises providing a patterned substrate, preferably a flexible patterned substrate, which will be described in more detail in connection with fig. 17 a. Step 1402 includes providing an uncured soft photopolymer plate as described in connection with FIG. 17 b. Step 1403 includes optional pre-treatment steps of the plate as described in connection with fig. 17 c-17 e. Step 1404 includes imprinting the substrate into a plate as described in connection with fig. 17f and 17 g. Step 1405 includes curing the plate as described in connection with fig. 17 h-17 j. The result 1406 is a flexographic printing plate or a cast plate resulting from steps 1401-1405.

Fig. 17a shows an end view of a flexible patterned substrate. At least a portion of one major surface of substrate 1510 includes relief features. The relief features are characterized by protrusions 1511 and recesses 1512. They may for example have a height (measured perpendicular to the substrate from the deepest depression to the highest protrusion) of 50nm to 150 μm. Together, the protrusions 1511 and depressions 1512 form an exemplary pattern that serves as the master pattern for the flexographic printing plate or casting plate prepared in the method of fig. 16. The pattern on the substrate may have relief features comprising any aspect ratio, any shape, any number of protrusions and/or depressions of any kind, having any distribution known in the art, any of which configurations may vary in any way, preferably as long as the pattern has a height of 50nm to 150 μm, such as 50nm to 75 μm, 50nm to 37 μm, 50nm to 15 μm, or 50nm to 7 μm.

Fig. 17b shows an end view of an uncured soft photopolymer plate comprising a protective mask 1520 and a photopolymer material 1521. The presence or absence of a protective mask 1520 in the uncured soft photopolymer plate is optional.

Figure 17c shows an end view of the step of curing one side of the plate, which is the same as the plate of figure 17 b. A curing source 1534 (e.g., an ultraviolet light or electron beam emitter) emits curing energy 1533 (e.g., heat and/or light) that at least partially cures an exterior of the photopolymer material such that the photopolymer material has a cured portion 1532 and an uncured portion 1531. For example, the curing source (for use with any of the curing steps disclosed herein) may be a degrf Concept 400ECLF plate curing system (degrf Concept 400ECLF plate curing system) (available from Glunz & Jensen (Ringsted, Denmark)).

Fig. 17d shows an end view of the step of removing the mask 1540 from the plate. A removal process 1543 (such as laser ablation) includes removing the mask 1540 in a direction 1544 and exposing unmasked regions 1542 on the surface of the uncured portion 1541 of the photopolymer material. To prepare plate 1540 for subsequent processing and/or imprinting, all masks may be removed, as described below, such that all first sides 1542 become maskless regions. It is also possible to remove only a portion of the protective mask 1540. In this case, the unmasked areas may be continuous or discontinuous; for example, the mask may be ablated using a CDI Spark 4835 in-line UV digital flexo image layout machine (ESKO available from Ghent (Belgium)).

Figure 17e shows an end view of the step of pre-treating the plate. A treatment source 1552, such as a nozzle, doctor blade, or draw down bar, provides a treatment 1553 that partially treats at least a portion of the exterior of the uncured portion 1550 of the plate, for example, to improve its ability to break free of the surface upon contact. An example of such a treatment is spraying a thin silicone coating. The uncured portions 1551 may be partially or completely processed.

Fig. 17f shows an end view of the step of imprinting a flexible patterned substrate 1560 into the exposed surface of uncured portions 1561 of a soft photopolymer plate. Opposing

inward forces

1563 and 1564 provide pressure that urges base plate 1560 and the plate against each other such that the pattern of base plate 1560 is provided onto the plate, and the protrusions and depressions of the pattern shape at least the outer portion of uncured portion 1561 into a reverse image of the pattern of base plate 1560. The protrusions and depressions of the relief features of substrate 1560 become the depressions and protrusions of the relief features on the plate. The opposing inward force may be provided by various mechanical devices known in the art, including, for example, a compression roller as shown in FIG. 17 g; the embossing step may also include heating (e.g., by heaters providing conduction, convection, and/or radiation) before and/or during embossing to further soften the soft photopolymer plate.

Fig. 17g shows a side view of a portion of a mechanical device that may be used for the step of imprinting a flexible patterned substrate 1570 into the exposed surface of the uncured portion 1571 of the soft photopolymer plate. The first roller 1574 rotates counter-clockwise 1576 and the second roller 1575 rotates clockwise 1577. The

rollers

1574 and 1575 together provide a distribution of opposing inward forces that urge the substrate 1570 and plate against each other such that as the substrate 1570 and plate pass 1573 between the

rollers

1574 and 1575, the pattern of the substrate 1570 is imparted to the plate. The pair of

rolls

1574 and 1575 may be provided from a roll laminator (with or without heating) as is known in the art, including, for example, a LUX laminator model 62 Pro S available from MacDermid, Inc. The substrate and plate may be passed one or more times through one or more pairs of such rollers, with or without a carrier sheet on either or both sides. Alternatively, other types of laminators or presses (with or without rollers) as known in the art may be used.

Figure 17h shows an end view of a step of partially curing one side of the plate. Here, the plate is still in contact with the flexible patterned substrate 1580 resulting from the imprinting step of fig. 17f and/or 17 g. The substrate 1580 has material properties that allow curing energy to pass through, such as translucency. A first curing source 1586 is located outside of the substrate 1580 and emits curing energy 1585 through the substrate 1580. Which partially cures at least a portion of the uncured portion 1581 of the photopolymer material. A second curing source 1584 is located outside of the cured portion of the substrate 1582 and emits curing energy 1583 through the panel. The panel has material properties that allow the curing energy to pass through, such as translucency. Thus, at least a portion of the uncured portion 1581 of the photopolymer material is cured such that the uncured portion 1581 becomes at least partially cured. Thus, the substrate 1580 can be more easily removed from the board without distorting or damaging the pattern formed on the board. It is also possible that one or more curing sources are used on only one side. Typically, the curing energy falls within the UV spectrum, such as UV-a (315nm to 400nm wavelength), UV-B (280nm to 315nm wavelength), and UV-C (100nm to 280nm wavelength), and may be provided by various sources configured to provide such wavelengths, such as mercury bulbs or LED fixtures. Alternatively, the partial curing step is replaced with a full curing step such that the partially cured section 1581 is fully cured. Alternatively, the partial curing step is omitted such that the partially cured portion 1581 is uncured.

Figure 17i shows an end view of one side of the plate. The flexible patterned substrate 1590 is removed 1595 from the plate, for example by pulling or peeling. The photopolymer material of the plate has cured

portions

1592 and 1591 which may be uncured, partially cured or fully cured according to previous steps. At least a portion of portion 1591 includes protrusions 1594 and recesses 1593 that together form an exemplary pattern that is the resulting pattern on the flexographic printing plate.

Figure 17j shows an end view of the step of fully curing the photopolymer material of the plate. A first curing source 1506, located outside the portion 1501 of the plate, emits curing energy 1505 that travels to the portion 1501 and helps to fully cure the portion 1501. A second curing source 1504 located outside the curing portion 1502 of the plate emits curing energy 1503 that travels through the curing portion 1502 having material properties (e.g., translucency) that allow the curing energy to pass through. The curing energy 1503 helps to fully cure the portion 1501 such that the portion 1501 becomes fully cured. Thus, the pattern formed on the board is finally cured, and the board is further prepared for final use.

Alternatively, 1506 is a first processing source that emits the debonding energy 1505 that travels to the portion 1501 and helps to fully cure the portion 1501 through further polymerization of the photopolymer material. 1504 is a second processing source that emits de-binding energy 1503 that travels through portion 1502, which facilitates further polymerization of the photopolymer material. Thus, the pattern formed on the board is finally cured, and the board is further prepared for final use.

One or more processing sources may be used on only one side. The cured photopolymer plate can be detackified in any other manner known in the art, for example by immersing the plate in one or more chemical solutions, such as a halogen solution. The step of debonding the plate is optional. Typically, the release energy falls within the UV-C spectrum (100nm to 280nm wavelength).

FIG. 18 is a flow chart showing the steps of preparing a patterned flexographic printing plate or casting plate according to the present invention. Step 1601 comprises providing a rigid patterned substrate, preferably a patterned steel plate, which will be described in more detail in connection with fig. 19 a. Step 1602 includes providing a polymeric material, preferably polypropylene. Step 1603 includes heating the polymeric material to bring it to a molten or malleable state. Step 1604 includes delivering the molten or malleable polymeric material onto a substrate, for example as described in connection with fig. 19 b. Step 1605 includes cooling the polymeric material. The resulting 1606 is a flexographic printing plate or casting plate produced by step 1601-1605.

Fig. 19a shows an end view of a rigid patterned substrate. At least a portion of one major surface of the substrate 1701 includes relief features. The relief features are characterized by protrusions 1702 and depressions 1703. They may for example have a height (measured perpendicular to the substrate from the deepest depression to the highest protrusion) of 50nm to 150 μm. Together, the protrusions 1702 and depressions 1703 form an exemplary pattern that serves as a master pattern for a flexographic printing plate or casting plate prepared in the method of fig. 18. The pattern on the substrate may have relief features comprising any aspect ratio, any shape, any number of protrusions and/or depressions of any kind, having any distribution known in the art, any of which configurations may vary in any way, preferably as long as the pattern has a height of 50nm to 150 μm, such as 50nm to 75 μm, 50nm to 37 μm, 50nm to 15 μm, or 50nm to 7 μm.

Fig. 19b shows an injection molding apparatus. Solid polymeric material is added to the vessel 1723 via hopper 1724. The container 1723 is heatable such that the polymeric material may melt or become malleable in the container 1723. Alternatively, the polymeric material may be added to the container 1723 in an already molten or malleable state. From the vessel 1723, molten or malleable polymeric material is passed through a nozzle 1722 into a cavity 1721 defined by the mold 1720. Mold 1720 comprises a rigid patterned substrate as shown in fig. 19 a.

Fig. 20 illustrates one example of a micro-optical image wrapping system 1800 by a side view. The system includes a substrate 1810, an ink layer 1820 having a microimage 1830, and a varnish layer 1840. A layer of varnish 1840 is superimposed on the layer of ink 1820. The inner surface of the varnish layer 1840 is in contact with the ink layer. The outer surface of varnish layer 1840 faces away from ink layer 1820 and substrate 1810. A plurality of relief features 1850 are disposed on an outer surface of the varnish layer 1840. Each of the images 1830 superimposes a relief feature 1850 having at least the same maximum diameter as the image 1830 and centered on top of the image 1830.

The dimensions and values disclosed herein are not to be understood as being strictly limited to the exact numerical values recited. Rather, unless otherwise specified, each such dimension is intended to mean both the recited value and a functionally equivalent range surrounding that value. For example, a dimension disclosed as "40 mm" is intended to mean "about 40 mm".

Claims

1. A method for printing 3D micro-optical images on a packaging system, the method comprising:

2. The method of claim 1, wherein the substrate is a rigid non-porous polymeric material selected from the group consisting of high density polyethylene, low density polyethylene, linear low density polyethylene, polypropylene, and polyethylene terephthalate.

3. The method of any preceding claim, wherein the image is printed by a method selected from the group consisting of inkjet printing, in-mold labeling, transfer printing, rotogravure printing, screen printing, letterpress printing, offset printing, and flexographic printing.

4. The method of any preceding claim, wherein the image is a microimage.

5. The method of any preceding claim, wherein the images are arranged in a regular pattern.

6. The method according to any of the preceding claims, wherein the image size is at least 20 μm, preferably in the range of 20 to 300 μm, and wherein the distance between the images is in the range of 1 to 1mm, preferably 5 to 100 μm, more preferably 10 to 50 μm.

7. The method of any preceding claim, wherein the varnish is thermally curable, photo-curable, or both, preferably UV curable, preferably wherein the varnish is an acrylic varnish.

8. The method of any preceding claim, wherein the relief features on the varnish layer are formed by a film-free casting process using a flexographic casting plate.

9. The method according to any one of the preceding claims, wherein the relief features have a height in the range of 50nm to 150 μ ι η, preferably 10 μ ι η to 30 μ ι η, a diameter of at least 20 μ ι η, preferably in the range of 20 μ ι η to 300 μ ι η, and the shape is a partial sphere shape.

10. The method of any preceding claim, wherein the relief features and the images have the same pattern, preferably wherein each image is superimposed with a relief feature having at least the same maximum diameter as the image and centrally disposed over the top of the image.

11. The method of any of the preceding claims, wherein the image is printed by flexographic printing using a flexographic printing plate, or wherein the relief features are formed by a film-free casting process using a flexographic casting plate, or both, and wherein the flexographic printing plate, the flexographic casting plate, or both are prepared by a process comprising injection molding, blow molding, embossing, printing, engraving, or a combination thereof.

12. The method of claim 11, wherein the flexographic printing plate, the flexographic casting plate, or both are flexible and made of a plastic material (preferably polypropylene).

13. The method of any one of claim 11 or claim 12, wherein the flexographic printing plate, the flexographic casting plate, or both are prepared by a method comprising:

i. providing a flexible patterned substrate;

14. The method of any one of claim 11 or claim 12, wherein the flexographic casting plate is prepared by a method comprising:

(i) providing a rigid patterned substrate, preferably a patterned steel plate prepared by laser pulse engraving; and

A 3D micro-optic image packaging system, the packaging system comprising:

A. a substrate having a first major surface and a second major surface;

B. a plurality of images on at least a portion of the first major surface;